/*
##########################################################################
#                          COPYRIGHT NOTICE                              #
##########################################################################
#                                                                        #
# Copyright (c) 2006 Genome Research Ltd.                                #
# Author: The Cancer Genome Project IT group cancerit@sanger.ac.uk       #
#                                                                        #
# THIS SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       #
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     #
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. #
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   #
# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   #
# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      #
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 #
#                                                                        #
# This code is free software; you can redistribute it and/or modify it   #
# under the terms of the BSD License.                                    #
#                                                                        #
# Any redistribution or derivation in whole or in part including any     #
# substantial portion of this code must include this copyright and       #
# permission notice.                                                     #
#                                                                        #
##########################################################################
*/

package uk.ac.sanger.cgp.dbcon.support;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.net.BindException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.URLEncoder;
import java.util.Date;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Locale;
import java.util.Properties;
import java.util.StringTokenizer;
import java.util.TimeZone;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * <p>
 * <strong>Modified from original source to add a terminate server method and
 * removing method deprecated in version 1.4. Logging also done in
 * commons logging rather than STDOUT apart from {@link #main(String[])}
 * </strong>.
 * 
 * <p>
 * A simple, tiny, nicely embeddable HTTP 1.0 server in Java
 * 
 * <p>
 * NanoHTTPD version 1.1, Copyright &copy; 2001,2005-2007 Jarno Elonen
 * (elonen@iki.fi, http://iki.fi/elonen/)
 * 
 * <p>
 * <b>Features + limitations: </b>
 * <ul>
 * 
 * <li> Only one Java file </li>
 * <li> Java 1.1 compatible </li>
 * <li> Released as open source, Modified BSD licence </li>
 * <li> No fixed config files, logging, authorization etc. (Implement yourself
 * if you need them.) </li>
 * <li> Supports parameter parsing of GET and POST methods </li>
 * <li> Supports both dynamic content and file serving </li>
 * <li> Never caches anything </li>
 * <li> Doesn't limit bandwidth, request time or simultaneous connections </li>
 * <li> Default code serves files and shows all HTTP parameters and headers</li>
 * <li> File server supports directory listing, index.html and index.htm </li>
 * <li> File server does the 301 redirection trick for directories without '/'</li>
 * <li> File server supports simple skipping for files (continue download) </li>
 * <li> File server uses current directory as a web root </li>
 * <li> File server serves also very long files without memory overhead </li>
 * <li> Contains a built-in list of most common mime types </li>
 * <li> All header names are converted lowercase so they don't vary between
 * browsers/clients </li>
 * 
 * </ul>
 * 
 * <p>
 * <b>Ways to use: </b>
 * <ul>
 * 
 * <li> Run as a standalone app, serves files from current directory and shows
 * requests</li>
 * <li> Subclass serve() and embed to your own program </li>
 * <li> Call serveFile() from serve() with your own base directory </li>
 * 
 * </ul>
 * 
 * See the end of the source file for distribution license (Modified BSD
 * licence)
 */
public class NanoHttpd {
  
  private Log log = LogFactory.getLog(this.getClass());
  
  public Log getLog() {
    return log;
  }
  
  // ==================================================
  // API parts
  // ==================================================

  /**
   * Override this to customize the server.
   * <p>
   * 
   * (By default, this delegates to serveFile() and allows directory listing.)
   * 
   * @parm uri Percent-decoded URI without parameters, for example "/index.cgi"
   * @parm method "GET", "POST" etc.
   * @parm parms Parsed, percent decoded parameters from URI and, in case of
   *       POST, data.
   * @parm header Header entries, percent decoded
   * @return HTTP response, see class Response for details
   */
  public Response serve(String uri, String method, Properties header,
      Properties parms) {
    getLog().debug(method + " '" + uri + "' ");

    Enumeration e = header.propertyNames();
    while (e.hasMoreElements()) {
      String value = (String) e.nextElement();
      getLog().debug("  HDR: '" + value + "' = '"
          + header.getProperty(value) + "'");
    }
    e = parms.propertyNames();
    while (e.hasMoreElements()) {
      String value = (String) e.nextElement();
      getLog().debug("  PRM: '" + value + "' = '"
          + parms.getProperty(value) + "'");
    }

    return serveFile(uri, header, new File("."), true);
  }

  /**
   * HTTP response. Return one of these from serve().
   */
  public class Response {
    /**
     * Default constructor: response = HTTP_OK, data = mime = 'null'
     */
    public Response() {
      this.status = HTTP_OK;
    }

    /**
     * Basic constructor.
     */
    public Response(String status, String mimeType, InputStream data) {
      this.status = status;
      this.mimeType = mimeType;
      this.data = data;
    }

    /**
     * Convenience method that makes an InputStream out of given text.
     */
    public Response(String status, String mimeType, String txt) {
      this.status = status;
      this.mimeType = mimeType;
      this.data = new ByteArrayInputStream(txt.getBytes());
    }

    /**
     * Adds given line to the header.
     */
    public void addHeader(String name, String value) {
      header.put(name, value);
    }

    /**
     * HTTP status code after processing, e.g. "200 OK", HTTP_OK
     */
    public String status;

    /**
     * MIME type of content, e.g. "text/html"
     */
    public String mimeType;

    /**
     * Data of the response, may be null.
     */
    public InputStream data;

    /**
     * Headers for the HTTP response. Use addHeader() to add lines.
     */
    public Properties header = new Properties();
  }

  /**
   * Some HTTP response status codes
   */
  public static final String HTTP_OK = "200 OK",
      HTTP_REDIRECT = "301 Moved Permanently",
      HTTP_FORBIDDEN = "403 Forbidden", HTTP_NOTFOUND = "404 Not Found",
      HTTP_BADREQUEST = "400 Bad Request",
      HTTP_INTERNALERROR = "500 Internal Server Error",
      HTTP_NOTIMPLEMENTED = "501 Not Implemented";

  /**
   * Common mime types for dynamic content
   */
  public static final String MIME_PLAINTEXT = "text/plain",
      MIME_HTML = "text/html",
      MIME_DEFAULT_BINARY = "application/octet-stream";

  // ==================================================
  // Socket & server code
  // ==================================================

  public NanoHttpd(int port) throws IOException {
    this(port,false);
  }
  
  /**
   * Starts a HTTP server to given port.
   * <p>
   * Throws an IOException if the socket is already in use
   */
  public NanoHttpd(int port, boolean ignoreIfAlreadyBound) throws IOException {
    myTcpPort = port;
    
    try {
      final ServerSocket ss = new ServerSocket(myTcpPort);
      Thread t = new Thread(new Runnable() {
        public void run() {
          try {
            while (true) {
              if(closeServer) {
                break;
              }
              new HTTPSession(ss.accept());
            }
            ss.close();
          }
          catch (IOException e) {
            getLog().error("Problem with IO", e);
          }
        }
      });
      t.setDaemon(true);
      t.start();
    }
    catch(BindException e) {
      if(!ignoreIfAlreadyBound) {
        throw e;
      }
    }
  }
  
  private boolean closeServer = false;
  
  /**
   * Signals to the server to terminate the HTTP server's thread
   */
  public void closeServer() {
    this.closeServer = true;
  }

  /**
   * Starts as a standalone file server and waits for Enter.
   */
  public static void main(String[] args) {
    System.out.println("NanoHTTPD 1.1 (C) 2001,2005-2007 Jarno Elonen\n"
        + "(Command line options: [port] [--licence])\n");

    // Show licence if requested
    int lopt = -1;
    for (int i = 0; i < args.length; ++i)
      if (args[i].toLowerCase().endsWith("licence")) {
        lopt = i;
        System.out.println(LICENCE + "\n");
      }

    // Change port if requested
    int port = 80;
    if (args.length > 0 && lopt != 0)
      port = Integer.parseInt(args[0]);

    if (args.length > 1 && args[1].toLowerCase().endsWith("licence"))
      System.out.println(LICENCE + "\n");

    NanoHttpd nh = null;
    try {
      nh = new NanoHttpd(port);
    }
    catch (IOException ioe) {
      System.err.println("Couldn't start server:\n" + ioe);
      System.exit(-1);
    }
    nh.myFileDir = new File("");

    System.out.println("Now serving files in port " + port + " from \""
        + new File("").getAbsolutePath() + "\"");
    System.out.println("Hit Enter to stop.\n");

    try {
      System.in.read();
    }
    catch (Throwable t) {
    }
    ;
  }

  /**
   * Handles one session, i.e. parses the HTTP request and returns the response.
   */
  private class HTTPSession implements Runnable {
    public HTTPSession(Socket s) {
      mySocket = s;
      Thread t = new Thread(this);
      t.setDaemon(true);
      t.start();
    }

    public void run() {
      try {
        InputStream is = mySocket.getInputStream();
        if (is == null)
          return;
        BufferedReader in = new BufferedReader(new InputStreamReader(is));

        // Read the request line
        StringTokenizer st = new StringTokenizer(in.readLine());
        if (!st.hasMoreTokens())
          sendError(HTTP_BADREQUEST,
              "BAD REQUEST: Syntax error. Usage: GET /example/file.html");

        String method = st.nextToken();

        if (!st.hasMoreTokens())
          sendError(HTTP_BADREQUEST,
              "BAD REQUEST: Missing URI. Usage: GET /example/file.html");

        String uri = decodePercent(st.nextToken());

        // Decode parameters from the URI
        Properties parms = new Properties();
        int qmi = uri.indexOf('?');
        if (qmi >= 0) {
          decodeParms(uri.substring(qmi + 1), parms);
          uri = decodePercent(uri.substring(0, qmi));
        }

        // If there's another token, it's protocol version,
        // followed by HTTP headers. Ignore version but parse headers.
        // NOTE: this now forces header names uppercase since they are
        // case insensitive and vary by client.
        Properties header = new Properties();
        if (st.hasMoreTokens()) {
          String line = in.readLine();
          while (line.trim().length() > 0) {
            int p = line.indexOf(':');
            header.put(line.substring(0, p).trim().toLowerCase(), line
                .substring(p + 1).trim());
            line = in.readLine();
          }
        }

        // If the method is POST, there may be parameters
        // in data section, too, read it:
        if (method.equalsIgnoreCase("POST")) {
          long size = 0x7FFFFFFFFFFFFFFFl;
          String contentLength = header.getProperty("content-length");
          if (contentLength != null) {
            try {
              size = Integer.parseInt(contentLength);
            }
            catch (NumberFormatException ex) {
            }
          }
          String postLine = "";
          char buf[] = new char[512];
          int read = in.read(buf);
          while (read >= 0 && size > 0 && !postLine.endsWith("\r\n")) {
            size -= read;
            postLine += String.valueOf(buf, 0, read);
            if (size > 0)
              read = in.read(buf);
          }
          postLine = postLine.trim();
          decodeParms(postLine, parms);
        }

        // Ok, now do the serve()
        Response r = serve(uri, method, header, parms);
        if (r == null)
          sendError(HTTP_INTERNALERROR,
              "SERVER INTERNAL ERROR: Serve() returned a null response.");
        else
          sendResponse(r.status, r.mimeType, r.header, r.data);

        in.close();
      }
      catch (IOException ioe) {
        try {
          sendError(HTTP_INTERNALERROR, "SERVER INTERNAL ERROR: IOException: "
              + ioe.getMessage());
        }
        catch (Throwable t) {
        }
      }
      catch (InterruptedException ie) {
        // Thrown by sendError, ignore and exit the thread.
      }
    }

    /**
     * Decodes the percent encoding scheme. <br/> For example:
     * "an+example%20string" -> "an example string"
     */
    private String decodePercent(String str) throws InterruptedException {
      try {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < str.length(); i++) {
          char c = str.charAt(i);
          switch (c) {
          case '+':
            sb.append(' ');
            break;
          case '%':
            sb.append((char) Integer.parseInt(str.substring(i + 1, i + 3), 16));
            i += 2;
            break;
          default:
            sb.append(c);
            break;
          }
        }
        return new String(sb.toString().getBytes());
      }
      catch (Exception e) {
        sendError(HTTP_BADREQUEST, "BAD REQUEST: Bad percent-encoding.");
        return null;
      }
    }

    /**
     * Decodes parameters in percent-encoded URI-format ( e.g.
     * "name=Jack%20Daniels&pass=Single%20Malt" ) and adds them to given
     * Properties.
     */
    private void decodeParms(String parms, Properties p)
        throws InterruptedException {
      if (parms == null)
        return;

      StringTokenizer st = new StringTokenizer(parms, "&");
      while (st.hasMoreTokens()) {
        String e = st.nextToken();
        int sep = e.indexOf('=');
        if (sep >= 0)
          p.put(decodePercent(e.substring(0, sep)).trim(), decodePercent(e
              .substring(sep + 1)));
      }
    }

    /**
     * Returns an error message as a HTTP response and throws
     * InterruptedException to stop furhter request processing.
     */
    private void sendError(String status, String msg)
        throws InterruptedException {
      sendResponse(status, MIME_PLAINTEXT, null, new ByteArrayInputStream(msg
          .getBytes()));
      throw new InterruptedException();
    }

    /**
     * Sends given response to the socket.
     */
    private void sendResponse(String status, String mime, Properties header,
        InputStream data) {
      try {
        if (status == null)
          throw new Error("sendResponse(): Status can't be null.");

        OutputStream out = mySocket.getOutputStream();
        PrintWriter pw = new PrintWriter(out);
        pw.print("HTTP/1.0 " + status + " \r\n");

        if (mime != null)
          pw.print("Content-Type: " + mime + "\r\n");

        if (header == null || header.getProperty("Date") == null)
          pw.print("Date: " + gmtFrmt.format(new Date()) + "\r\n");

        if (header != null) {
          Enumeration e = header.keys();
          while (e.hasMoreElements()) {
            String key = (String) e.nextElement();
            String value = header.getProperty(key);
            pw.print(key + ": " + value + "\r\n");
          }
        }

        pw.print("\r\n");
        pw.flush();

        if (data != null) {
          byte[] buff = new byte[2048];
          while (true) {
            int read = data.read(buff, 0, 2048);
            if (read <= 0)
              break;
            out.write(buff, 0, read);
          }
        }
        out.flush();
        out.close();
        if (data != null)
          data.close();
      }
      catch (IOException ioe) {
        // Couldn't write? No can do.
        try {
          mySocket.close();
        }
        catch (Throwable t) {
        }
      }
    }

    private Socket mySocket;
  };

  /**
   * URL-encodes everything between "/"-characters. Encodes spaces as '%20'
   * instead of '+'.
   */
  private String encodeUri(String uri) {
    String newUri = "";
    StringTokenizer st = new StringTokenizer(uri, "/ ", true);
    while (st.hasMoreTokens()) {
      String tok = st.nextToken();
      if (tok.equals("/"))
        newUri += "/";
      else if (tok.equals(" "))
        newUri += "%20";
      else {
//        newUri += URLEncoder.encode(tok);
        // For Java 1.4 you'll want to use this instead:
        try { 
          newUri += URLEncoder.encode( tok, "UTF-8" ); 
        } 
        catch (UnsupportedEncodingException e ) {
          throw new RuntimeException("Cannot encode", e);
        }
      }
    }
    return newUri;
  }

  private int myTcpPort;

  File myFileDir;

  // ==================================================
  // File server code
  // ==================================================

  /**
   * Serves file from homeDir and its' subdirectories (only). Uses only URI,
   * ignores all headers and HTTP parameters.
   */
  public Response serveFile(String uri, Properties header, File homeDir,
      boolean allowDirectoryListing) {
    // Make sure we won't die of an exception later
    if (!homeDir.isDirectory())
      return new Response(HTTP_INTERNALERROR, MIME_PLAINTEXT,
          "INTERNAL ERRROR: serveFile(): given homeDir is not a directory.");

    // Remove URL arguments
    uri = uri.trim().replace(File.separatorChar, '/');
    if (uri.indexOf('?') >= 0)
      uri = uri.substring(0, uri.indexOf('?'));

    // Prohibit getting out of current directory
    if (uri.startsWith("..") || uri.endsWith("..") || uri.indexOf("../") >= 0)
      return new Response(HTTP_FORBIDDEN, MIME_PLAINTEXT,
          "FORBIDDEN: Won't serve ../ for security reasons.");

    File f = new File(homeDir, uri);
    if (!f.exists())
      return new Response(HTTP_NOTFOUND, MIME_PLAINTEXT,
          "Error 404, file not found.");

    // List the directory, if necessary
    if (f.isDirectory()) {
      // Browsers get confused without '/' after the
      // directory, send a redirect.
      if (!uri.endsWith("/")) {
        uri += "/";
        Response r = new Response(HTTP_REDIRECT, MIME_HTML,
            "<html><body>Redirected: <a href=\"" + uri + "\">" + uri
                + "</a></body></html>");
        r.addHeader("Location", uri);
        return r;
      }

      // First try index.html and index.htm
      if (new File(f, "index.html").exists())
        f = new File(homeDir, uri + "/index.html");
      else if (new File(f, "index.htm").exists())
        f = new File(homeDir, uri + "/index.htm");

      // No index file, list the directory
      else if (allowDirectoryListing) {
        String[] files = f.list();
        String msg = "<html><body><h1>Directory " + uri + "</h1><br/>";

        if (uri.length() > 1) {
          String u = uri.substring(0, uri.length() - 1);
          int slash = u.lastIndexOf('/');
          if (slash >= 0 && slash < u.length())
            msg += "<b><a href=\"" + uri.substring(0, slash + 1)
                + "\">..</a></b><br/>";
        }

        for (int i = 0; i < files.length; ++i) {
          File curFile = new File(f, files[i]);
          boolean dir = curFile.isDirectory();
          if (dir) {
            msg += "<b>";
            files[i] += "/";
          }

          msg += "<a href=\"" + encodeUri(uri + files[i]) + "\">" + files[i]
              + "</a>";

          // Show file size
          if (curFile.isFile()) {
            long len = curFile.length();
            msg += " &nbsp;<font size=2>(";
            if (len < 1024)
              msg += curFile.length() + " bytes";
            else if (len < 1024 * 1024)
              msg += curFile.length() / 1024 + "."
                  + (curFile.length() % 1024 / 10 % 100) + " KB";
            else
              msg += curFile.length() / (1024 * 1024) + "." + curFile.length()
                  % (1024 * 1024) / 10 % 100 + " MB";

            msg += ")</font>";
          }
          msg += "<br/>";
          if (dir)
            msg += "</b>";
        }
        return new Response(HTTP_OK, MIME_HTML, msg);
      }
      else {
        return new Response(HTTP_FORBIDDEN, MIME_PLAINTEXT,
            "FORBIDDEN: No directory listing.");
      }
    }

    try {
      // Get MIME type from file name extension, if possible
      String mime = null;
      int dot = f.getCanonicalPath().lastIndexOf('.');
      if (dot >= 0)
        mime = (String) theMimeTypes.get(f.getCanonicalPath()
            .substring(dot + 1).toLowerCase());
      if (mime == null)
        mime = MIME_DEFAULT_BINARY;

      // Support (simple) skipping:
      long startFrom = 0;
      String range = header.getProperty("Range");
      if (range != null) {
        if (range.startsWith("bytes=")) {
          range = range.substring("bytes=".length());
          int minus = range.indexOf('-');
          if (minus > 0)
            range = range.substring(0, minus);
          try {
            startFrom = Long.parseLong(range);
          }
          catch (NumberFormatException nfe) {
          }
        }
      }

      FileInputStream fis = new FileInputStream(f);
      fis.skip(startFrom);
      Response r = new Response(HTTP_OK, mime, fis);
      r.addHeader("Content-length", "" + (f.length() - startFrom));
      r.addHeader("Content-range", "" + startFrom + "-" + (f.length() - 1)
          + "/" + f.length());
      return r;
    }
    catch (IOException ioe) {
      return new Response(HTTP_FORBIDDEN, MIME_PLAINTEXT,
          "FORBIDDEN: Reading file failed.");
    }
  }

  /**
   * Hashtable mapping (String)FILENAME_EXTENSION -> (String)MIME_TYPE
   */
  private static Hashtable theMimeTypes = new Hashtable();
  static {
    StringTokenizer st = new StringTokenizer("htm    text/html "
        + "html   text/html " + "txt    text/plain " + "asc    text/plain "
        + "gif    image/gif " + "jpg    image/jpeg " + "jpeg   image/jpeg "
        + "png    image/png " + "mp3    audio/mpeg " + "m3u    audio/mpeg-url "
        + "pdf    application/pdf " + "doc    application/msword "
        + "ogg    application/x-ogg " + "zip    application/octet-stream "
        + "exe    application/octet-stream "
        + "class    application/octet-stream ");
    while (st.hasMoreTokens())
      theMimeTypes.put(st.nextToken(), st.nextToken());
  }

  /**
   * GMT date formatter
   */
  private static java.text.SimpleDateFormat gmtFrmt;
  static {
    gmtFrmt = new java.text.SimpleDateFormat("E, d MMM yyyy HH:mm:ss 'GMT'",
        Locale.US);
    gmtFrmt.setTimeZone(TimeZone.getTimeZone("GMT"));
  }

  /**
   * The distribution licence
   */
  private static final String LICENCE = "Copyright (C) 2001,2005 by Jarno Elonen <elonen@iki.fi>\n"
      + "\n"
      + "Redistribution and use in source and binary forms, with or without\n"
      + "modification, are permitted provided that the following conditions\n"
      + "are met:\n"
      + "\n"
      + "Redistributions of source code must retain the above copyright notice,\n"
      + "this list of conditions and the following disclaimer. Redistributions in\n"
      + "binary form must reproduce the above copyright notice, this list of\n"
      + "conditions and the following disclaimer in the documentation and/or other\n"
      + "materials provided with the distribution. The name of the author may not\n"
      + "be used to endorse or promote products derived from this software without\n"
      + "specific prior written permission. \n"
      + " \n"
      + "THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR\n"
      + "IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES\n"
      + "OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.\n"
      + "IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,\n"
      + "INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT\n"
      + "NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,\n"
      + "DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY\n"
      + "THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT\n"
      + "(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE\n"
      + "OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.";
}
